Expansion-cam



(No Model) 0. P'. LAWRENCE.

EXPANSION 0AM. No. 583,688. Patented June 1,1897.

Z 5 JCT/670609" UNTTED STATES PATENT EEICE.

CHARLES P. LAIVRENCE, NORWVAY, MAINE.

EXPANSION-CAM.

SPECIFICATION forming part of Letters Patent No. 583,688, dated June 1,1897. Application filed February 7, 1895. Serial No. 537,574. (Nomodel.)

To aZZ whom it may con/acre.

Be it known that I, CHARLES P. LAWRENCE, of Norway, county of Oxford,State of Maine, have invented an Improvement in Expansion- Cams, ofwhich the following description, in connection with the accompanyingdrawings, is a specification, like letters and figures on the drawingsrepresenting like parts.

This invention has for its object to provide a novel cam capable ofexpansion by the operator for the purpose of varying its throw asnecessity may require. In many machinessuch, for example, as lasting orpulling-over machines, where the lasting operation or the operation ofthe nippers which act upon the leatheris controlled by a cam-there hasheretofore to my knowledge been no means for varying the action of thelasting devices or nippers for' pulling over or stretching the leatherto a greater or less extent according to its weight or condition.

By the use of an expansion-cam embodying my invention, if it is foundthat the usual throw of the cam is insufficient to properly stretch orpull over the leather, the operator by a simple movement may vary thethrow of the cam to increase or magnify its action.

In the drawings I have illustrated my invention in connection with adetail of a lasting-machine, Figure 1 showing in front elevation myinvention in operative position. Fig. 2 is an enlarged side elevation ofthe cam, partly broken away, the operating-wedge being omitted. Fig. 3is a central vertical section taken on the line 3 3 of Fig. 2.

Referring to the drawings, while I have illustrated my invention as usedin connection with a lasting-machine, yet it should be understood thatmy invention is not limited as to its use to any particular machines orclass of machines.

The cam is composed of a body H and two side plates H H the body havingan adjustable throw point or block H adapted to slide radially betweenthe side plates referred to and provided with a dovetailed groove, whichis entered by the corresponding dovetailed Wedge H shown as rigidlyconnected with a groove-collar H splined on the main shaft A androtatable therewith, but having an back and forth as required on theshaft A a bracket 6 being shown supporting a roll e to be operated bythe cam, the roll e being held against the cam by the usual spring (notshown) in the spring-barrel 6 In use the cam is positively operated byreciprocating the collar II on the main shaft, the wedge H then slidingback and forth in the dovetailed groove of the throw-block transverselyof the cam. This serves to expand and contract the cam, the cam-surfacethereof changing in shape correspondingly, within the two extremepositions shown in Fig. 3 by full and dotted lines.

While such a cam is particularly useful in lasting and pulling-overmachines, yet its use is not limited in this respect, for it may beapplied to any kind of machine where a variable cam movement is desired.

Having described one form of my invention, what I claim, and desire tosecure by Letters Patent, is

1. An expansion-cam, having a movable throw-block carried thereby as aconstituent part thereof, combined with a wedge carried by said cam, andinterlocked with the throwblock, interlocking means being providedtherefor on the wedge and throw-block and means to move said wedge tovary the position of the throw-block, substantially as described.

2. An expansion-cam, havingathrow member movable therein and provided atits inner end with a dovetailed edge, a grooved collar,

and its attached dovetailed wedge, cooperating with and to positivelyvary the position of the said throw member out and in rela tively to theremaining cam-surface of the cam, substantially as described.

3. A cam-body, having a throw member forming a constituent part thereof,said throw member being movable relatively thereto in a radialdirection, whereby said cam may be expanded or contracted and thecam-surface thereof changed in shape, and a Wedge inovname to thisspecification in the presence of ing parallel to the axis of the saidcam-body, two subscribing Witnesses.

said wedge having means whereby the same 1 j i j r 9 1 E. 1s movablyconnected to said throw member CHAhLES 1 RI AU to positively move thesame in and out, snb- \Vitnesses:

stantially as described. HOWARD D. SMITH,

In testimony whereof I have signed my M. P. SMITH.

